/// <summary>
/// Trace information for an unhandled exception.
/// Each request handler should perform its logic within a try block, and call this handler within the catch block.
/// </summary>
/// <param name="ex">the exception caught at top level</param>
/// <param name="tracer">Tracer that will be used to send telemetry on the failure</param>
/// <param name="fallbackTracer">Fallback tracer, in case the tracer fails</param>
public static void TraceUnhandledException(Exception ex, ITracer tracer, TraceWriter fallbackTracer)
{
// Trace the full exception details
string errorToTrace = $"Top level exception: {ex}";
try
{
// Write to trace
tracer?.TraceError(errorToTrace);
// Report the exception
if (ex != null && tracer != null)
{
AggregateException aggregateException = ex as AggregateException;
if (aggregateException != null)
{
aggregateException.InnerExceptions.ToList().ForEach(tracer.ReportException);
}
else
{
tracer.ReportException(ex);
}
}
// Flush all traces
tracer?.Flush();
}
catch (Exception traceException)
{
try
{
// Try to write to the fallback tracer
fallbackTracer?.Error($"Tracer failed - using fallback tracer. Tracer error: {traceException}");
fallbackTracer?.Error(errorToTrace);
fallbackTracer?.Flush();
}
catch (Exception fallbackTraceException)
{
try
{
// Try to write to console
Console.WriteLine($"Tracer failed - using fallback tracer. Tracer error: {traceException}");
Console.WriteLine($"Fallback tracer failed - using console. Fallback tracer error: {fallbackTraceException}");
Console.WriteLine(errorToTrace);
}
catch (Exception)
{
// Just swallow, nothing better to do here..
}
}
}
}
public static void Flush()
{
_tracer.Flush();
}